You are Here: Home >< Maths

C3 Differentiation watch

1. Could anyone help me with a differentiation question? Basically you see how the function (3x^2+5x-9)^1/3 can be differentiated to 1/3(6x+5)(3x^2+5x-9)^-2/3 so there is 2 brackets, could u help me differentiate ((x^3-4x+4)/2)^1/2 in the same way?

Thank you for any help im really struggling.
2. Look this up on Wolfram alpha
3. (Original post by emperorCode)
Look this up on Wolfram alpha
I tried but they don't differentiate it into the way I want.
4. (Original post by mansnothot)
Could anyone help me with a differentiation question? Basically you see how the function (3x^2+5x-9)^1/3 can be differentiated to 1/3(6x+5)(3x^2+5x-9)^-2/3 so there is 2 brackets, could u help me differentiate ((x^3-4x+4)/2)^1/2 in the same way?

Thank you for any help im really struggling.
Separate into 0.5^0.5 * (x^3-4x+4)^1/2, as 0.5^0.5 is a constant it shouldnt hinder ur ability to differentiate the other expression. Just remember to multiply by 0.5^0.5 after uve differentiated (x^3-4x+4)^1/2.
5. (Original post by Shaanv)
Separate into 0.5^0.5 * (x^3-4x+4)^1/2, as 0.5^0.5 is a constant it shouldnt hinder ur ability to differentiate the other expression. Just remember to multiply by 0.5^0.5 after uve differentiated (x^3-4x+4)^1/2.
So would this give me my differential function?
6. (Original post by mansnothot)
So would this give me my differential function?
This will give u the gradient function. Are u talking about a specific question or just in general in ur intial post?
7. (Original post by Shaanv)
This will give u the gradient function. Are u talking about a specific question or just in general in ur intial post?
no i just needed to differentiate that because I didnt know how to. If it's okay can I attempt to differentiate it and could you tell me if I'm correct?

Thanks.
8. I went on this thinking it would be related to GCSE OCR Chemistry (Unit C3).

9. (Original post by RickiestRick)
I went on this thinking it would be related to GCSE OCR Chemistry (Unit C3).

SMH, change ur name to mortiest morty. 😂
10. (Original post by Shaanv)
SMH, change ur name to mortiest morty. 😂
But I'm arrogant, and that's exactly who Rick is
11. (Original post by RickiestRick)
I went on this thinking it would be related to GCSE OCR Chemistry (Unit C3).

That's such a dank unit!

Wait you do new spec

e . w
12. (Original post by mansnothot)
Could anyone help me with a differentiation question? Basically you see how the function (3x^2+5x-9)^1/3 can be differentiated to 1/3(6x+5)(3x^2+5x-9)^-2/3 so there is 2 brackets, could u help me differentiate ((x^3-4x+4)/2)^1/2 in the same way?

Thank you for any help im really struggling.
13. (Original post by perspirationting)
Loooooooooool I'm done
14. (Original post by mansnothot)
Could anyone help me with a differentiation question? Basically you see how the function (3x^2+5x-9)^1/3 can be differentiated to 1/3(6x+5)(3x^2+5x-9)^-2/3 so there is 2 brackets, could u help me differentiate ((x^3-4x+4)/2)^1/2 in the same way?

Thank you for any help im really struggling.
You use the chain rule for the first question and the quotient rule for the second.

Not sure if this is allowed but I've attached an explanation of how to use the chain rule regarding the first question. Hope it makes sense and helps.

Spoiler:
Show

For some bizarre reason, I can't upload the final answer, which is 1/3(6x + 5)(3x^2 + 5 - 9)^-2/3)

Attached Images

15. Is it this...
Spoiler:
Show

y = (½(x^3 - 4x + 4))^½
= ½^½ * (x^3 - 4x + 4)^½
dy/dx = ½^½ * ½(x^3 - 4x + 4)^-½ * (3x^2 - 4)
= ½^3/2 * (x^3 - 4x + 4)^-½ * (3x^2 - 4)

∴ = ½^3/2 (x^3 - 4x + 4)^-½(3x^2 - 4)

16. (Original post by amkay)
Is it this...
Spoiler:
Show

y = (½(x^3 - 4x + 4))^½
= ½^½ * (x^3 - 4x + 4)^½
dy/dx = ½^½ * ½(x^3 - 4x + 4)^-½ * (3x^2 - 4)
= ½^3/2 * (x^3 - 4x + 4)^-½ * (3x^2 - 4)

∴ = ½^3/2 (x^3 - 4x + 4)^-½(3x^2 - 4)

I got up to this part ½^½ * ½(x^3 - 4x + 4)^-½ * (3x^2 - 4)
but I don't understand why ½^½ * ½ becomes ½^3/2
17. (Original post by mansnothot)
I got up to this part ½^½ * ½(x^3 - 4x + 4)^-½ * (3x^2 - 4)
but I don't understand why ½^½ * ½ becomes ½^3/2
I'm just adding powers so ½^½ * ½^1 = ½^(½ + 1) = ½^3/2
just like how x^2 * x^3 = x^(2+3) = x^5

Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: October 28, 2017
Today on TSR

Thought he was 19... really he's 14

University open days

Wed, 25 Jul '18
2. University of Buckingham
Wed, 25 Jul '18
3. Bournemouth University
Wed, 1 Aug '18
Poll
Useful resources

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

How to use LaTex

Writing equations the easy way

Study habits of A* students

Top tips from students who have already aced their exams

Chat with other maths applicants